Diamond filtering is a great way to get rid of those little hairs that hang over your bob line when your client moves their hair around. The diamond shape sectioning gives this technique its name, and I use it on all of my bobs! Diamond Filtering is a specialized hair-cutting technique that can help refine and perfect a bob haircut's shape. By using diamond-shaped sections and careful trimming techniques, stylists can create a customized, polished look tailored to each client's individual needs and preferences.